Malicious Office (OLE) / .XLS — malware analysis report

Static analysis result for SHA-256 624c1ffb5d398d36…

MALICIOUS

Office (OLE) / .XLS

36.5 KB Created: 2020-11-25 10:39:19 Authoring application: Microsoft Excel
MD5: b0030bf6fb3c43758d0b25ba12920e0f SHA-1: 9759332bcb130f4b343ed743f7e82379f51bc6ef SHA-256: 624c1ffb5d398d36648c6ccb8fc62d7e9ddc994c5bfaf530b7344978fe86b9eb
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is an Excel spreadsheet containing Excel 4.0 (XLM) macros, specifically an Auto_Open function. This indicates an attempt to automatically execute code when the document is opened, a common technique for delivering malware. The presence of dangerous formula APIs further supports this malicious intent.

Heuristics 3

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
1215b138be94970203f7763d45d3cd25fe3ac8497fab186e746659482354da4b		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6660 bytes

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